Where the first of the above questions is concerned – MR structure – several
scenarious have been proposed over the last hundred years
[1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}.
A much acclaimed approach considers (so-called) network glasses as continuously-
and homogeneously-disordered media at the local (atomic), MR and long-range
lenght scale: it is the so-called continuous-random-network (CRN) model of
Zachariasen and Warren [3]}, [4]}. However, other scientists have
suggested to further elaborate upon the CRN approach in favour of heterogeneous
mesoscopic scenarios [1]}, [2]}, [5]}, [6]}, [7]}, [10]}.
Moreover, scenarios have been proposed where the dynamical heterogeneities
(DH) known to characterise the supercooled liquid state [20]} continue to
exist (albeit somewhat more statically) also below \(T_g\) , the nominal temperature
of glass formation [8]}, [9]}, [11]}, [24]}.
One of these non-CRN scenarios views glasses as made up of solid-like particle
regions jammed together somewhat below \(T_g\)  and presenting liquid-like
regions in-between [11]}. Remarkably, the liquid-like regions between
the solid ones may become the sources of collective orbital magnetic moments that
appear to generate an intrinsic contribution to the glass sample's magnetisation
mimicking the known Langevin paramagnetism from isolated impurities.
In the ordinary silicate glasses the latter are typically from Fe and the Fe-group trace
elements [26]}. The extra intrinsic magnetic moments issue from
specialized, magnetic-field sensitive tunneling systems (TS) believed to be
responsible for a plethora of magnetic effects at low temperatures in glasses
[11]}, [28]}, [29]}. These and the more standard TS (the so-called
two-level systems (TLS) [30]}, [31]}, [29]}) might be part of the
degrees of freedom sought for in order to investigate the physical properties of
glasses at higher temperatures too [33]}.
